Telephone system.



L. c. BYGRAVE. TELEPHGNE SYSTEM. Y"

APPLICATION FILED MAY`24. I9I6.

1,249@ Patenteasept. 18,1917

2 SHEETS-SHEET I.

L. C. BYGHAVE. TELEPHQNE SYSTEM.'

APPLICATION FILED MY 24. |916.

Pat-erle Sept, X8, NU.

2 SHEETS-SMEET 2.

LEONARD (JI-ARLES BYGRAVE, U-

AUTOMATC TELElHlSl'E Cf" TELENE Application filed iiay 24,

To all 'u1/wm it may concern:

le it known that l, ljnoxenn @intentes Bsimvn, a subject ot the hline' o?E Great Britain, residing at li/larconi House, Strand, London, England, have invented .i l

Tenci useful improvements in 'elephono Systems, of which the following is a specification. rlhe invention relates to automat semi-automatic satellite exchange systems. Systems of this hind are known in which local connections are completed Within the local exchange without engaging any exl change line ,tor the duration ci the conversation. A calling subscriber at a local exchange may, for example, be automatically connected with an exchange line and through this with a selector at the central exchange. The selector is then directly operated by the irstlset ot' digit impulses which determines Whether the call is for the same local exchange or for another exchange. il" the call is for the same exchange, the connection including the exchange line is automatically released, and connection is made with connector at the local exchange which receives the remaining impulses and completes the connection.

According to the present system, a calling subscriber is first connected to discriminating means which are situated at the local exchange and are operated by the iirst set oi' digit impulses to determine the direction cit the call. lf the call is for another exchange, and only then, connecting means are operated to extend the connection to the central exchange where a'selector is operated immediately to select the exchange wanted. This is effected automatically by additional impulses which are sent from the local exchange before the next digit is dialed. Thus according to the present inventioi'i, the discriminating set of digit impulses which determines whether the call is for the'same or for another exchange has no eil'ect beyond the local exchange until the direction oit the call has been determined but, in case the call is for another exchange, is l ade eitective at that exchange before the next set of digit impulses is sent.

the ordinary Way by the following digit .lin the case of' a local call, the 'connection is completed in N53, ASSGNGR TO ETL-*IE RELAY SLGN'DON, ENGLAND.

SYSTEM.

Spectcation of Letters atent.

Patented Sept. i8, i913?.

sei-iai no. 99,574..

sible not to engage an exchange line until it has been ascertained that it is Wanted.

Vihe accompanying drawings show one form of the invention as applied to a system in which the connections are established by means oli relays only, Figure l being a animatie View showing a trunk and means for connecting it to outgoing trunks, while Fig. is a diagrammatic View of a selector for connecting the trunk to subscribers lines or 'for actuating the above connecting means.

A l a trunk line at a local exchange to 'which a calling' subscriber is automatica ly connected upon lifting the receiver, and before any digit of the Wanted number is dialed. Associated With. the trunk are two connecting relays T1 and T2 adapted to connect the trunk with either of two junctions 51 and J2' leading to the central eX- change, and, further, a relay selector consisting of relays R1 to R11 and five grou relays G1 to G5. The subscribers. lines lg ot the local exchange, Which may `be supposed to comprise subscribers numbered Sill to S60, are connected' to contacts of the up relays G1 to G5, each of which has a K of ten subscribers7 lines connected to its contacts, By means of the selectors R1 to it and the group relays G1 to G5. the trunk line i B can be connected in a known manner to any subscribers line over links Z by energizing the group relay G corresponding to the tens group of the Wanted subscriber, and the selector relay R corresponding to the units figure of the Wanted number. The selector also serves 'as a discriminator Vto determine Whether the call is for a subscriber o the same exchange or for the central exchange. A if by the first set of digit impulses the selector is set on to any position except that which corresponds to the local exchange, it operates to connect the trunk to the first idle junction by energizing the corresponding connecting relay T1 or T2, and to send a complementary number of digit impulses over the junction before the next digit is dialed. if, on the other hand, the selector is set on the position corresponding to the local exchange, viz., the eighth, it is released without extending the connection, and is operated by the next last set 'of impulses to complete the local conj mains in an operated position to uphold thei vro `nection, and the selector therefore now reconnection.

When a subscriber of the local exchange lifts his receiver, he is' automatically connected in any known manner to a trunk A B and his line ciicuit 1 is closed through an impulse relay l. VThe latter energizes over 2' 'a slow-acting guarding relay D which completes4 over the third wire H a holding circuit 3 for the connecting vmeans joining the subseribers line to the trunk. The subscriber now dials the rst digit of the wanted number. Upon the rst interruption of the line'circuit, relay l denergizes and completes a circuit 4 through a slow-acting change-over relay S and a circuit through the irstselector relay R1; Relay S energizes over 6 a slow-release control relay C1 which in turn energizes over 7 another slowreleasev controlrelay C2 which is retained over 8,' and R1.energizesover 9 relay R2 which is then retained over 101. Relay C1 .is retained over its contact 11 and relay R1 over its contact l2. Upon the impulse relay I re'e'nergizing, R1 releases. Onthe second y interruption of the line circuit, relay R3 lis 'operate/.i over 13 and locks itself over 14. Atthe same time R2 is connected over to the impulse: circuit at contact so that upon the impulse relay renergizmg R2 1s released; Similar operations take place for each interruption 'of the line circuit whereby R", R5, Re, ete., are operated successively.

At the en'd of the first set of impulses, S releases.' lf any other number but 8 has been dialed, circuit 16 is completed through the connecting relay T1, which energizes and connects trunk A B. with the junction J1, thereby cutting olf relay land closing the line circuit through the junction and a s'lowrelease holding relay E1., Relay T1 is retained over 17 and the circuit through the third wire H is maintained over 18. Relays I and D denergize. Relay T1, upon operating, completes an interruptor circuit 19 through a relay N which now gives impulses to the central exchange by interrupt-ing the linecireuit, and at the same time gives impulses to the selector over 20 and to relay lS over 21. VThe latter again energizes and maintains G1 which has maintained the selector in its .position over 22. By the and only Tlrand E1 remain energized lt dialed. These complementary impulses and the impulses for the succeeding digits operate in a well known manner a selector at the central exchange to select the exchange and subscriber wanted.

If the c'all is for a local subscriber, relay R is the 'last operatedby the first set of impulses, and when S denergizescircuit 16 is not completed. Relay C1 therefore falls oli' in due course and releases the selector.

The second setiof impulses isnow dialed. Relay S renergizes and operates over 23 relay C3 which is retained over 24. y Relays R1, R2, etc;, respond to the impulses as before, and at the end of the series S releases and completes circuit 25 through the group relay G corresponding to the relayR which is energized, that is, to the'digit dialed. Immediately after, relay C2 falls 0H and reI leases the selector which has been held over 26. l

By the next and last set of impulses` relay S is renergized which now completes circuit 27 through lthe control relay C4. This retains the selector over 28 after S has released, and the connection is thereby completed with the wanted subscriber-s line. By well known means not shown here, the subscriber is rung automatically. l/Vhen he answers, his line ci rcuit is closed through a relay l which may be used in the ordinary way to cut oil" the ringing circuit. The connection is severed and all relays denergized by the calling subscriber replacing his receiver.

What I claim is l. A telephone system comprising discriminating means situated in an exchange and adapted immediately it is operated by a setl of digit impulses to determine whether vthe call is for that exchange or for another,-

before the nextset of impulses issent inl from the sub-station and before a trunk to said other'exchange is taken into engagement, and means whereby, when the call is for the other exchan e, that same set of digit impulses' is ,madg at the other. exchange.

e selectively eective 2. A telephone system comprising dis-.-A

criminating .means situated in an exchange and adapted on being operated by al set of digit impulses to determine Whether the call is for that exchange' or for another, and' when the'A call-is -for that same exchange'to operate again in accordancev with the next 1s for that exchange or for' anotherbefore ist Leens/ie apparatus at ein the-i' exchange is talen iniao use, and ineens Whe-rele?, when the call is or che ozher elicnane, the; saine set ci digit impulses mede selecsively efective the other en: ige before the sending the nent set o difii, impulses, no other impulses beingeffective to operaie any epparatus at the local exchange.

e. ln telephone systemy che combination of local exchinge, a main exchange?. a, junction line from Vche local to the main eye change, a. selector at the local exchange adapted to be operatedin accordance with digit impulses io connecc with lines in the local exchange if call to local subscriber, and idapiefi when operated accord" ing to one set oi" digit impulses to discriminae between a call o the local exchange and a call ir main exchange means conrolled by the selector for extending to the junction line u, call or the main exchange, and ineens Ywhereby when 1lhe call is ior ihe nniin exchange that saine set of impulses is made selec-ively eiieci'iy'e at 'che main exchange.

A telephone system comprising at a local exchange an impulse respondei adapted to respond to all trains of impulses to effect e connccion within said local eirchange, a discrinimaing means responsive csnid iinpnise responder and adaoted to (lelerinine ii u call is for be local exchange or for amher.I and an i ipu se transmitting :fieri-fie whereby che discrninaing set of es is snede selffceii ly eifective ai; the

re ne nin, olf iinic sub-staioiicompris ouaoeo. in. en catene-ng ci: e and adapmg on ii-ing operated by sei4 ci dc'il impulses io determine Wne'cher the lio the@ exchange or 'i'or another an A ,i allier ci has been sent and in case the -call is for another exchangej -a complementary number of impulses is sent to said exchange before the next set of digit impulses.

7. A telephone system' comprising Cliscriniinating means situated in an exchange and adapted on being operated by a set of digit impulses to determine Whether -the call is for that exchange or for another,

and means whereby, after said set Ginn-- .leadingl to another exchange, discriminating;

means associated with said trunk line and adapea to be operated by a set of digit irnpulsesfto determine Wheher the call@ is for Jdie first or for 'the second exchange, means whereby a junction line is connected. with the trunk line after it has been ascerbaineol the?, "che call is 'for the second exchange, and .means whereby' said set of digit impulsesis 4 inade selectively eiective ai; the second eX- comprising means chance before the next set of digit impulses i is seni, i-he first aiiparans ai, che said second exchenge being arranged that il- Will respend to impulses complementary in Yanni her 'lathe iininilses for operating the discriniinating A oarei'ius and all ocher apparatus at the said second or local exchange being arranged to respond to direct irnpulses. 

